JPH05256179A - Engine control device - Google Patents

Abstract

PURPOSE:To secure a temperature correction factor corresponding correctly to the actual intake air temperature so as to improve control accuracy by correcting the correction factor of intake air temperature onto the higher side of intake air temperature at the time of a valve means being operated to open the communicating passage of each cylinder, compared to the non-operating time. CONSTITUTION:In a rotary piston engine 1, plural cylinders 4 are communicated with each other by a communicating passage 16, and each opening end of the communicating passage 16 to each cylinder 4 is set as a delay-closing intake port 17 closed later than an intake port 9. The communicating passage 16 is opened in the specified operating state by a control valve 18, and the control valve 18 is controlled by a control unit 31 on the basis of detection signals from an intake temperature sensor 33 and the like. At the opened time of the control valve 18, the correction factor of intake air temperature is corrected onto the higher side of intake air temperature compared to the valve closed time. This results in obtaining a temperature correction factor corresponding correctly to the actual intake air temperature in combustion chambers 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an engine, and more particularly to a control device for controlling an operating element of the engine in accordance with an actual temperature of intake air supplied to the engine.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Laid-Open Patent Publication No. 1-31872.
As disclosed in Japanese Unexamined Patent Publication No. 4 etc., the cylinders in a multi-cylinder engine are communicated with each other through a communication passage, and the opening end of each communication passage to each cylinder is a late-closed intake port that is closed later than the intake port. By opening the communication passage in a predetermined operating state, for example, in a low load region where the throttle opening is small, intake air is supplied from another cylinder to the combustion chamber in the intake stroke of a cylinder via the communication passage. It is known that the intake loss to the cylinder is reduced by the supply of so that the so-called engine pumping loss is reduced and the fuel consumption is improved.

[0003]

By the way, when the fuel supply amount to be supplied to the engine is set according to the intake air amount, the temperature of the intake air is detected by a sensor, and the intake charge amount is increased by the rise of the intake air temperature. When the temperature drops, the fuel supply amount is also reduced accordingly to maintain the air-fuel ratio appropriately.A temperature correction coefficient is set according to the detected intake air temperature, and this temperature is set. The basic fuel supply amount is corrected based on the correction coefficient.

The intake air temperature sensor is usually provided at the upstream end of the intake passage, such as an air flow meter or a surge tank. However, in the case where a plurality of cylinders of an engine are communicated with each other through a communication passage as in the above-described conventional case, intake air flows between the cylinders, so that the cylinder in the intake stroke is heated from the combustion chamber wall surface by another cylinder. The intake air thus supplied is supplied, and the actual intake air temperature becomes higher than the temperature detected by the sensor. Therefore, the temperature correction coefficient based on the intake air temperature detected by the sensor does not correspond to the actual intake air temperature, and as a result, the air-fuel ratio cannot be maintained properly.

In addition to a normal injector for injecting fuel into the intake passage of the engine, a direct injection injector for directly injecting fuel into the cylinder is provided to improve fuel efficiency in a low engine load range. In this way, fuel is injected and supplied only from the direct injection injector to the combustion chamber, and the combustibility is enhanced by stratification of the fuel in the combustion chamber, while in the high load region of the engine, in order to increase the output, the direct injection injector In addition to this, it is known to inject fuel from an injector in the intake passage.

In such an engine, when the injector in the intake passage is in the operating state, the fuel injected from the injector evaporates before it reaches the combustion chamber, so the heat of vaporization associated with the evaporation is removed. The intake air temperature in the combustion chamber drops by that much. Therefore, again, there is a problem that the temperature correction coefficient based on the intake air temperature detected by the sensor does not correspond to the actual intake air temperature.

The present invention has been made in view of the above points, and an object of the present invention is to provide a means for changing the intake air temperature downstream of the sensor for detecting the intake air temperature, as described above. By correcting the correction coefficient related to the intake air temperature in the operating state of the means, the temperature correction coefficient corresponding to the actual intake air temperature in the combustion chamber is obtained almost accurately to prevent erroneous correction related to the intake air temperature. To do.

[0008]

In order to achieve the above object, according to the invention of claim 1, a plurality of cylinders of an engine are communicated with each other through a communication passage, and intake air comes and goes between the cylinders via the communication passage. On the other hand, the correction coefficient of the intake air temperature is corrected to the high temperature side in the communication state between the cylinders.

Specifically, according to the present invention, a plurality of cylinders are communicated with each other, and a communication passage which is a late-closed intake port that closes an opening end of each cylinder later than an intake port and a predetermined engine. In an engine control device comprising a valve means that operates to open the communication path in an operating state,
When the valve means is in the operating state, the temperature correction coefficient correcting means is provided for correcting the correction coefficient of the intake air temperature supplied to the engine in a direction in which the intake air temperature becomes higher than in the non-operating state. Is.

According to the second aspect of the present invention, the fuel supply means for supplying the fuel to the cylinder and the intake passage of the engine are respectively provided, whereas the correction coefficient of the intake temperature is provided in the state where the fuel is supplied to the intake passage. Was corrected to the low temperature side.

That is, the present invention provides an engine control device comprising an in-cylinder fuel supply means for supplying fuel directly into the cylinder of the engine, and an intake passage fuel supply means for supplying fuel to the intake passage. When the passage fuel supply means is in the operating state, the temperature correction coefficient correcting means is provided for correcting the correction coefficient of the intake air temperature supplied to the engine in the direction in which the intake air temperature becomes lower than in the non-operating state. ..

[0012] In the invention of claim 3, the above-mentioned claim 1 or 2
The engine control device is configured to control the fuel supply amount of the engine based on the correction coefficient of the intake air temperature corrected by the temperature correction coefficient correction means.

[0013]

With the above construction, in the invention of claim 1, the temperature correction coefficient correcting means corrects the correction coefficient of the intake air temperature supplied to the engine in the direction of increasing the intake air temperature when the valve means is in the operating state. Therefore, even if the intake air whose temperature has risen from another cylinder flows into the in-cylinder combustion chamber through the communication passage, it is possible to obtain a temperature correction coefficient that almost exactly corresponds to the actual intake air temperature in the combustion chamber, It is possible to prevent erroneous correction related to the intake air temperature.

According to the second aspect of the present invention, the correction coefficient of the intake air temperature supplied to the engine is adjusted by the temperature correction coefficient correction means when the intake passage fuel supply means is operating and fuel is being supplied to the intake passage. It is corrected to the low side of the intake air temperature. Therefore, even if the intake air temperature in the combustion chamber is lowered by the heat of vaporization of the fuel supplied from the intake passage fuel supply means to the intake passage, a temperature correction coefficient that approximately corresponds to the actual intake air temperature in the combustion chamber is obtained. Therefore, it is possible to prevent erroneous correction of the intake air temperature.

According to the third aspect of the present invention, the fuel supply amount of the engine is controlled by the correction coefficient of the intake air temperature corrected by the temperature correction coefficient correction means, so that the air-fuel ratio of the engine can be appropriately maintained.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 3 shows the overall construction of Embodiment 1 of the present invention. Reference numeral 1 denotes a rotary piston engine having two cylinders 4 and 4, and this engine 1 has a pair of rotor housings 2 and 2 having a trochoidal surface on the inner circumference and an intermediate portion sandwiched between the rotor housings 2 and 2. Housing 3
And a pair of side housings (not shown) arranged outside each rotor housing 2. In each of the two cylinders 4 and 4 surrounded by these housings, the cylinder 4 is provided with three working chambers 5, 5, ...
The (combustion chamber) houses the rotor 6 that is partitioned.
The rotor 6 is supported by the output shaft 7 so as to be eccentrically rotatable, and the eccentric rotation of the rotor 6 causes the working chambers 5 to sequentially perform intake, compression, explosion (expansion), and exhaust strokes. 7 is rotationally driven.

Reference numeral 8 is an intake passage for supplying intake air into the working chamber 5 in the intake stroke. The intake passage 8 is branched into two parts on the downstream side of the surge tank 10, each downstream end of which is formed by an intake port 9 opening to the inner wall surface of the intermediate housing 3, and the intake port 9 is provided in the intake stroke of the rotor 6 Is opened and closed at a predetermined timing. Above surge tank 1
Reference numeral 0 is connected to an air cleaner (not shown) via a collective intake passage 11, and a throttle valve 12 for narrowing the intake passage 8 is arranged in the collective intake passage 11. Further, the surge tank 10 has a boost (intake negative pressure) downstream of the throttle valve 12.
A boost sensor 32 for detecting the temperature and a temperature sensor 33 for detecting the intake air temperature (intake air temperature) are provided.
Further, injectors 13 for injecting and supplying fuel are arranged in the intake passages 8 near the intake ports 9 of the respective cylinders 4 on the downstream side of the surge tank 10.

On the other hand, 14 is an exhaust passage for exhausting exhaust gas from the working chamber 5 in the exhaust stroke, and the upstream end of the exhaust passage 14 is constituted by an exhaust port 15 opening to the peripheral wall surface of each rotor housing 2. The exhaust port 15 is opened and closed by the rotor 6 at a predetermined timing in the exhaust stroke.

Further, the two cylinders 4 and 4 are communicated with each other by a communication passage 16. This communication passage 16
The opening end of each of the cylinders 4 is opened to the inner wall surface of the intermediate housing 3 on the front side of the intake port 9 in the rotor rotation direction, and is closed later than the intake port 9 by the rotor 6 in the intake stroke. It is said that. And
In the intake stroke of one cylinder 4 of the engine 1, its working chamber 5
The intake air is supplied to the (combustion chamber) from the other cylinder 4 through the communication passage 16, and the intake loss of the intake air is reduced to reduce the pumping loss of the engine 1.

A control valve 18, which is a rotary valve as valve means, is disposed in the middle of the communication passage 16. This valve 18 is rotated by the drive of an actuator (not shown) to open and close the communication passage 16,
As will be described later, the engine 1 operates to open the communication passage 16 in a predetermined operating state (see FIG. 2). In FIG.
Reference numeral 19 is a spark plug.

The injector 13 and the control valve 18 are controlled by the control unit 31. The control unit 31 includes an output signal of a throttle sensor 34 for detecting the opening TVO of the throttle valve 12, an output signal of a boost sensor 32, an output signal of a temperature sensor 33, and an engine 1
The output signal of the rotation sensor 35 for detecting the rotation speed R of is input. Here, the control unit 3
Setting of the temperature correction coefficient used to calculate the fuel injection amount in 1.
A signal processing procedure when switching control of the control valve 18 will be described with reference to FIG. First, in the first step S1, it is determined whether the engine speed is 500 rpm or more. This determines whether or not the engine 1 has started. When the determination is YES, the process proceeds to step S2, and the map of the temperature correction coefficient used to calculate the fuel injection amount is set in the map A. This temperature correction coefficient map A shows, for example, a temperature correction coefficient of 1.0820 when the intake air temperature is −20 ° C. and a temperature correction coefficient of 1.820 when the intake air temperature is 0 ° C. As the intake air temperature increases, the temperature correction coefficient decreases. Next, at step S3, the throttle opening TVO detected by the throttle sensor 34 and the rotation sensor 35
Each data of the engine speed R detected by the above is read, and the operating state of the engine 1 is judged by comparing these data with the set value in step S4. That is, FIG.
As shown in, the throttle opening TVO is TVO1 ≤ TV
O ≦ TVO2 is not satisfied, or the engine speed R is R1
If ≤R≤R2 is not satisfied and the engine 1 is not in the steady state, the determination is NO. At this time, the process proceeds to step S5, the control valve 18 is closed, and the map of the temperature correction coefficient is switched to the map A in step S6. On the other hand, the throttle opening TVO is TVO1 ≤ TVO ≤
It is in TVO2 and the engine speed R is R1 ≤ R ≤ R
When it is 2, the determination is YES, and at this time, the control valve 18 is opened in step S7, and the map of the temperature correction coefficient is switched to the map B in step S8. In this map B, for example, the intake air temperature is −20 °
When C, the temperature correction coefficient is 1.0625, and when the intake air temperature is 0 ° C, the temperature correction coefficient is 1.007.
As in Map 1, the higher the intake air temperature, the smaller the temperature correction coefficient becomes, but the side where the temperature correction coefficient becomes smaller than that of Map A, that is, the intake air temperature becomes higher. Is set to.

Further, a procedure for obtaining the fuel injection amount from the injector 13 based on the temperature correction coefficient will be described with reference to FIG. Based on the engine boost detected by the boost sensor 32 and the engine rotation speed detected by the rotation sensor 35, the basic fuel injection amount is calculated from a predetermined map. On the other hand, as described in the above flow, after selecting the map of the temperature correction coefficient from the engine speed and the throttle opening, the temperature correction coefficient corresponding to the intake air temperature detected by the temperature sensor 33 is calculated from the map. .. After that, the final fuel injection amount is calculated from the temperature correction coefficient and the fuel basic injection amount obtained above, and the signal is output to each injector 13.

In this embodiment, when the control valve 18 is in the operating state and the communication passage 16 is open, the steps S4, S7 and S8 in the flow shown in FIG. , Engine 1
The temperature correction coefficient correction means 36 is configured to correct the correction coefficient of the intake air temperature supplied to the intake air temperature increasing direction. Then, as shown in FIG. 4, the fuel supply amount of the engine 1 is controlled by the correction coefficient of the intake air temperature corrected by the temperature correction coefficient correction means 36.

Therefore, in the above embodiment, during operation of the engine 1, the throttle sensor 34 detects the throttle opening TVO and the rotation sensor 35 detects the engine rotation speed R, and the operation of the engine 1 is performed based on these data. The state is determined. As shown in FIG. 2, the throttle opening TVO is TVO1≤TVO≤TV.
If it is not in O2 or the engine speed R is R1 ≤ R ≤ R
2 and the engine 1 is not in the steady state, the control valve 18 is closed and the map of the temperature correction coefficient is selected in the map A.

On the other hand, the throttle opening TVO is TV
O1≤TVO≤TVO2 and engine speed R
Is R1≤R≤R2, and the control valve 18 is opened when the operating state of the engine 1 is in a steady state. With the opening operation of the control valve 18, intake air is supplied from the other cylinder 4 to the operation chamber 5 in the intake stroke of one cylinder 4 of the engine 1 via the communication passage 16 and the intake air to the operation chamber 5 is changed. Engine 1 with reduced intake loss
The pumping loss is reduced, and the fuel efficiency of the engine 1 can be improved.

At this time, since the intake air supplied from the other cylinder 4 to the cylinder 4 in the intake stroke is being heated from the wall surface of the working chamber 5 in the other cylinder 4, the actual inside of the working chamber 5 is reduced. The intake air temperature becomes higher than the temperature detected by the temperature sensor 33, and the temperature correction coefficient set based on the intake air temperature detected by the sensor 33 may not correspond to the actual intake air temperature. However, in this embodiment, when the control valve 18 is in the operating state, the map of the temperature correction coefficient is switched from the map A to the map B, and the map B has a smaller temperature correction coefficient than the map A as a whole and the intake air Since the temperature is set to the high temperature side, the correction coefficient of the intake air temperature supplied to the engine 1 is corrected in the direction of increasing the intake air temperature. As a result, even if the intake air whose temperature has risen from the other cylinders 4 flows into the cylinder 4 through the communication passage 16, it is possible to obtain a temperature correction coefficient that almost exactly corresponds to the actual intake air temperature in the working chamber 5. Therefore, it is possible to prevent the erroneous correction of the intake air temperature and appropriately maintain the air-fuel ratio of the engine 1.

In this embodiment, the rotary piston engine 1 is targeted, but the present invention can also be applied to a reciprocating engine.

(Second Embodiment) FIGS. 5 to 7 show a second embodiment of the present invention. In this embodiment, the heat of vaporization of the injected fuel is a factor that changes the temperature of the intake air to the engine 1 in the intake passage 8 on the downstream side of the temperature sensor 33 for detecting the intake air temperature. The same parts as those in FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, a reciprocating engine 1'is targeted as shown in FIG. This engine 1 '
Includes a cylinder 21 (cylinder) and a piston 22 reciprocatingly fitted therein, and the piston 22 defines a combustion chamber 23 in the cylinder 21. Two
Reference numeral 4 denotes an intake valve that opens and closes an intake port 9 that is a downstream end of the intake passage 8, and 26 denotes an exhaust valve that opens and closes an exhaust port 15 that is an upstream end of the exhaust passage 14. A throttle valve 12 is provided in the intake passage 8, and a boost sensor 3 is provided downstream thereof.
2 and the temperature sensor 33, and further downstream thereof, an intake pipe injection injector 13 as an intake passage fuel supply means for injecting fuel into the intake passage 8 is arranged. The output signal of the throttle sensor 34 that detects the opening of the throttle valve 12 is input to the control unit 31 together with the signals of the boost sensor 32 and the temperature sensor 33.

On the side wall of the cylinder 21, a combustion chamber 23
A direct injection injector 28 is mounted as an in-cylinder fuel supply means for directly supplying the fuel to the cylinder. The injector 28 is controlled to be opened and closed by a control unit 31 together with the intake pipe injection injector 13. The signal processing procedure when setting the temperature correction coefficient used in the calculation of the fuel injection amount in the control unit 31 will be described with reference to FIG. Steps S1 to S
The processes up to 3 are the same as those in the first embodiment. At step S4 ', as shown in FIG. 6, the throttle opening TVO is changed to TVO≥
It is determined whether TVO1 is present and the engine speed R is R≥R1. If this determination is TVO <TVO1 or R <R1 and the engine 1'is NO in the low load range or low rotation range, the process proceeds to step S5 ', in which fuel is injected and supplied only from the direct injection injector 28. In order to improve fuel efficiency, stratified combustion is performed in the combustion chamber 23. Thereafter, the map of the temperature correction coefficient is switched to the map B in step S6.

On the other hand, the determination in step S4 'is Y
When ES (TVO ≧ TVO1 and R ≧ R1),
In step S7 ', the fuel is injected and supplied not only from the direct injection injector 28 but also from the intake pipe injection injector 13 to increase the output of the engine 1'. Then, in step S8, the map of the temperature correction coefficient is set to map A.
Switch to.

The procedure for obtaining the fuel injection amount from the injectors 13 and 28 based on the temperature correction coefficient is the same as in the first embodiment (see FIG. 4).

In this embodiment, by the steps S4 ', S7' and S8 in the flow shown in FIG. 1, the intake pipe injection injector 13 is supplied to the engine 1'when the intake pipe injection injector 13 is in the operating state, as compared to the non-operating state. The temperature correction coefficient correction means 36 'is configured to correct the correction coefficient of the intake air temperature, which decreases the intake air temperature.

In this embodiment, during operation of the engine 1 ', the operating state of the engine 1'is based on the throttle opening TVO detected by the throttle sensor 34 and the engine rotation speed R detected by the rotation sensor 35. Is determined, and as shown in FIG. 6, the engine 1'is TVO <TV
When in the low load range of O1 or in the low rotation range of R <R1, the fuel is injected only from the direct injection injector 28 to the engine 1 ', which improves the fuel efficiency by stratified combustion in the combustion chamber 23. Planned. At this time, the map of the temperature correction coefficient is selected as the map B.

On the other hand, when the engine 1'is in the high load and high rotation region of TVO≥TVO1 and R≥R1, fuel is injected and supplied not only from the direct injection injector 28 but also from the intake pipe injection injector 13. The output of the engine 1'increases. At this time, the fuel injected from the intake pipe injector 13 evaporates before reaching the combustion chamber 23, and the heat of vaporization accompanying the evaporation lowers the intake air temperature in the cylinder 21.
The actual intake air temperature therein becomes higher than the temperature detected by the temperature sensor 33, and the temperature correction coefficient set based on the intake air temperature detected by the sensor 33 may not correspond to the actual intake air temperature. However, also in this embodiment, in the state where the fuel is injected from the intake pipe injection injector 13,
Since the map of the temperature correction coefficient is selected as the map A in which the temperature correction coefficient is set to be larger than the map B as a whole, the correction coefficient of the intake temperature supplied to the engine 1'is It is corrected to a lower value. As a result, even if the intake air temperature in the combustion chamber 23 decreases due to the heat of vaporization that accompanies the evaporation of the fuel injected from the intake pipe injector 13, a temperature correction that approximately corresponds to the actual intake air temperature in the combustion chamber 23. The coefficient is obtained, and the erroneous correction of the intake air temperature can be prevented, so that the air-fuel ratio of the engine 1'can be properly maintained.

In each of the above-mentioned embodiments, the correction coefficient of the intake air temperature is used for controlling the fuel injection amount of the engine 1 ', but it can also be used for controlling the ignition timing of the engine, for example.

[0038]

As described above, according to the first aspect of the present invention, a plurality of cylinders of the engine are communicated with each other through the communication passage, and the opening end of each of the communication passages to each cylinder is delayed with respect to the intake port. In a control device for an engine in which the intake passage is closed and the communication passage is opened in a predetermined operating state of the engine, in a communication state between cylinders, a correction coefficient of the intake temperature supplied to the engine is set in a direction in which the intake temperature increases. It was corrected to. According to the invention of claim 2, in a control device for an engine, which is provided with fuel supply means for supplying fuel to each of the cylinder of the engine and the intake passage, the intake passage fuel supply means is in an operating state and fuel is supplied to the intake passage. When the intake air is supplied, the correction coefficient of the intake air temperature is corrected so that the intake air temperature becomes lower. Therefore, according to these inventions, due to the communication between the cylinders, the intake air whose temperature has risen from another cylinder flows into the cylinder through the communication passage, or the intake air temperature in the combustion chamber is increased by the heat of vaporization of the fuel supplied to the intake passage. Even if the temperature decreases, it is possible to effectively prevent erroneous correction of the intake temperature due to the difference between the actual intake temperature in the combustion chamber and the intake temperature detected on the upstream side of the intake passage.

According to the third aspect of the present invention, the air-fuel ratio of the engine can be properly maintained by controlling the fuel supply amount of the engine by the correction coefficient of the corrected intake air temperature.

[Brief description of drawings]

FIG. 1 is a flowchart showing a signal processing procedure performed by a control unit according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a valve opening / closing region map in the first embodiment.

FIG. 3 is an explanatory diagram showing the overall configuration of the first embodiment.

FIG. 4 is a block diagram showing a process for determining a fuel injection amount in the control unit of the first embodiment.

FIG. 5 is a view corresponding to FIG. 1 showing a second embodiment.

FIG. 6 is a characteristic diagram showing a region map of an injection method in the second embodiment.

FIG. 7 is an explanatory diagram showing an overall configuration of a second embodiment.

[Explanation of symbols]

 1, 1'engine 4 cylinder 5 working chamber (combustion chamber) 8 intake passage 9 intake port 13 injector (intake passage fuel supply means) 16 communication passage 17 late closing intake port 18 control valve (valve means) 21 cylinder (cylinder) 23 Combustion chamber 28 Direct injection injector (in-cylinder fuel supply means) 31 Control unit 33 Temperature sensor 36, 36 'Temperature correction coefficient correction means

Claims (3)

[Claims] 1. A communication passage that connects a plurality of cylinders to each other and has an opening end to each cylinder that is a late-closed intake port that is closed later than an intake port, and a communication passage that connects the cylinders in a predetermined operating state of the engine. In an engine control device having valve means that operates to open, when the valve means is in an operating state, the correction coefficient of the intake air temperature supplied to the engine is set to a direction in which the intake air temperature becomes higher than in a non-operating state. An engine control device comprising temperature correction coefficient correction means for correcting the temperature. 2. A control device for an engine, comprising: an in-cylinder fuel supply means for supplying fuel directly into a cylinder of an engine; and an intake passage fuel supply means for supplying fuel to an intake passage. When the engine is in the operating state, the engine control device is provided with temperature correction coefficient correcting means for correcting the correction coefficient of the intake air temperature supplied to the engine in the direction in which the intake air temperature becomes lower than in the non-operating state. .. 3. The engine control device according to claim 1 or 2, wherein the fuel supply amount of the engine is controlled based on the correction coefficient of the intake air temperature corrected by the temperature correction coefficient correction means. Characteristic engine control device.